1. Field of the Invention
The present invention relates in general to containers and in particular to methods and apparatus for opening collapsible containers.
2. Description of the Related Art
Collapsible bags, such as plastic trash bags and cloth laundry bags, have been in use for many years. Plastic trash bags have been particularly popular because of their convenience. Among other things, plastic bags in their collapsed form are easy to package for sale and easy to store. Moreover, they come is a range of sizes, from the large bags intended for disposing of leaves and similar yard trash to the smaller bags used in the household for disposing of kitchen waste and similar refuse. Once filled with refuse, the opening in the trash bag need only be fastened closed, for example with a twist tie, and the entire package appropriately sent for final disposal.
Even in light of their substantial advantages, there are many problems with the construction and use of plastic trash bags. First of all, because they are collapsible, the must be supported by a trash can or barrel, at least until they are substantially filled. In addition to support for the collapsible walls, a can or barrel is also normally required to maintain the bag opening spread wide enough for refuse to easily be inserted. Further, the thin walls of plastic are easily punctured or cut when sharp objects are tossed in to the bag. Finally, plastic bags are often difficult to open because the plastic walls typically stick together, especially at the lower extremities which are difficult to reach by hand.
Several ideas have been put forth for dealing the problem of supporting empty or near empty trash bags without the need for a trash bin or can. One of these ideas is embodied in U.S. Pat. No. 4,457,483 to Gagne. Here, a sheet of flexible plastic is rolled and then inserted into the opening of a trash bag as the support structure. This design however has at least two major disadvantages. First, the bag must be expanded by hand or by forcing the cylinder of plastic apart by hand after insertion into the bag. Second, because the plastic tube tends to collapse back into the coiled position, fasteners are required to keep the plastic uncoiled and the bag expanded.
A similar idea is disclosed in U.S. Pat. No. 5,226,554 to Dauphanis. In this case a sheet of strong flexible material is used as a trash bag liner. Specifically, the liner is made of polyethylene, which even if rolled, does not expand rapidly and generate enough force to completely open the trash bag from the opening to the bottom. Moreover, "locks" are provided to keep the ends of the liner together and the structure rigid.
Thus, the need has arisen for apparatus and methods for opening and supporting collapsible containers, such as plastic trash bags. Such apparatus and methods should be able to separate adjacent walls of the container, even if they are temporarily adhering to each other, quickly and with minimal hand work by the user. Further, these methods and apparatus should not require the use of fasteners for either maintaining support of the bag or the structural integrity of the apparatus itself.